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Diffstat (limited to '')
| -rw-r--r-- | lib/md2.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/lib/md2.c b/lib/md2.c new file mode 100644 index 0000000..29afdba --- /dev/null +++ b/lib/md2.c @@ -0,0 +1,192 @@ +/* Functions to compute MD2 message digest of files or memory blocks. + according to the definition of MD2 in RFC 1319 from April 1992. + Copyright (C) 1995-1997, 1999-2003, 2005-2006, 2008-2023 Free Software + Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Adapted by Simon Josefsson from public domain Libtomcrypt 1.06 by + Tom St Denis. */ + +#include <config.h> + +/* Specification. */ +#include "md2.h" + +#include <string.h> +#include <sys/types.h> + +#include <minmax.h> + +static void md2_update_chksum (struct md2_ctx *md); +static void md2_compress (struct md2_ctx *md); + +/* Initialize structure containing state of computation. + (RFC 1319, 3.3: Step 3) */ +void +md2_init_ctx (struct md2_ctx *ctx) +{ + memset (ctx->X, 0, sizeof (ctx->X)); + memset (ctx->chksum, 0, sizeof (ctx->chksum)); + memset (ctx->buf, 0, sizeof (ctx->buf)); + ctx->curlen = 0; +} + +/* Put result from CTX in first 16 bytes following RESBUF. The result + must be in little endian byte order. */ +void * +md2_read_ctx (const struct md2_ctx *ctx, void *resbuf) +{ + memcpy (resbuf, ctx->X, 16); + + return resbuf; +} + +/* Process the remaining bytes in the internal buffer and the usual + prolog according to the standard and write the result to RESBUF. */ +void * +md2_finish_ctx (struct md2_ctx *ctx, void *resbuf) +{ + unsigned long i, k; + + /* pad the message */ + k = 16 - ctx->curlen; + for (i = ctx->curlen; i < 16; i++) + { + ctx->buf[i] = (unsigned char) k; + } + + /* hash and update */ + md2_compress (ctx); + md2_update_chksum (ctx); + + /* hash checksum */ + memcpy (ctx->buf, ctx->chksum, 16); + md2_compress (ctx); + + return md2_read_ctx (ctx, resbuf); +} + +/* Compute MD5 message digest for LEN bytes beginning at BUFFER. The + result is always in little endian byte order, so that a byte-wise + output yields to the wanted ASCII representation of the message + digest. */ +void * +md2_buffer (const char *buffer, size_t len, void *resblock) +{ + struct md2_ctx ctx; + + /* Initialize the computation context. */ + md2_init_ctx (&ctx); + + /* Process whole buffer but last len % 64 bytes. */ + md2_process_block (buffer, len, &ctx); + + /* Put result in desired memory area. */ + return md2_finish_ctx (&ctx, resblock); +} + +void +md2_process_bytes (const void *buffer, size_t len, struct md2_ctx *ctx) +{ + const char *in = buffer; + unsigned long n; + + while (len > 0) + { + n = MIN (len, (16 - ctx->curlen)); + memcpy (ctx->buf + ctx->curlen, in, (size_t) n); + ctx->curlen += n; + in += n; + len -= n; + + /* is 16 bytes full? */ + if (ctx->curlen == 16) + { + md2_compress (ctx); + md2_update_chksum (ctx); + ctx->curlen = 0; + } + } +} + +static const unsigned char PI_SUBST[256] = { + 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, + 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, + 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24, + 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251, + 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63, + 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50, + 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165, + 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210, + 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157, + 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27, + 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15, + 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197, + 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65, + 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123, + 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233, + 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228, + 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237, + 31, 26, 219, 153, 141, 51, 159, 17, 131, 20 +}; + +/* adds 16 bytes to the checksum */ +static void +md2_update_chksum (struct md2_ctx *ctx) +{ + int j; + unsigned char L; + + L = ctx->chksum[15]; + for (j = 0; j < 16; j++) + { + /* caution, the RFC says its "C[j] = S[M[i*16+j] xor L]" but the + reference source code [and test vectors] say otherwise. */ + L = (ctx->chksum[j] ^= PI_SUBST[(int) (ctx->buf[j] ^ L)] & 255); + } +} + +static void +md2_compress (struct md2_ctx *ctx) +{ + size_t j, k; + unsigned char t; + + /* copy block */ + for (j = 0; j < 16; j++) + { + ctx->X[16 + j] = ctx->buf[j]; + ctx->X[32 + j] = ctx->X[j] ^ ctx->X[16 + j]; + } + + t = (unsigned char) 0; + + /* do 18 rounds */ + for (j = 0; j < 18; j++) + { + for (k = 0; k < 48; k++) + { + t = (ctx->X[k] ^= PI_SUBST[(int) (t & 255)]); + } + t = (t + (unsigned char) j) & 255; + } +} + +/* Process LEN bytes of BUFFER, accumulating context into CTX. */ +void +md2_process_block (const void *buffer, size_t len, struct md2_ctx *ctx) +{ + md2_process_bytes (buffer, len, ctx); +} |